A context switch is the switching of a processing unit from one process or thread to another. A process is an executing instance of a program. A context is the contents of a processing unit's registers and program counter at any point in time. A register is a small amount of very fast memory inside the processing unit as opposed to the slower random access memory, or even slower read only memory, outside the processing unit. Context switching involves: 1) suspending the progression of one process and storing the context or state for that process in a memory, 2) retrieving the context of the next process from the memory and restoring it in the processing unit's registers, and 3) returning to the location indicated by the program counter to resume the process. A component is a process or a hardware device that transmits and/or receives information from another process and/or hardware device.
Security requires that non-secure resources cannot access secure data. An architecture supporting multiple independent levels of security (MILS) provides a hierarchy of security services, where each level uses the security services of a lower level to provide new security functionality. Each level is responsible only for its own security domain. A secure multi-level system (MLS) is one in which the system provides mechanisms to enforce mandated controls on the flow of information between components executing at different security levels. A system that supports MLS security tags objects with a classification level, tags processes with a clearance, and ensures that the data is manipulated by the processes according to the security policy.
A conventional transceiver system for a radio may comprise numerous processing subsystems for each channel. For example, a transceiver unit may contain a digital signal processing subsystem, a black processing subsystem, a cryptographic subsystem, a red processing subsystem, etc. for each channel. Traditional cryptographic systems dedicate a programmable algorithm processing unit (PAPU) to each physical channel within a device to control the separation between the information flows. When very large radio systems are considered, such as those having in excess of 30-40 (or more) channels, this redundant capability becomes expensive in terms of cost, weight, and volume. What is needed, therefore, is a system and a method that utilize a different interconnect methodology and structure to reduce the number of PAPUs, thereby providing cost, size, and/or weight savings while maintaining a fast response time. Further, there is a need for a system and a method that provides cost, size, and/or weight savings while supporting MILS.